Power control mechanism for jet powered aircraft



May 31, 1960 J. A. MORRISON 2,938,683

POWER CONTROL MECHANISM FOR JET POWERED AIRCRAFT Filed June 6, 1955 IN VEN TOR. JOHN A. MORRISON nited States Patent C) POWER CONTROL MECHANISM FOR JET i POWERED AIRCRAFT John A. Morrison, Seattle, Wash., assignor toBoeing Airplane Company, Seattle, Wash., a corporation of Delaware Filed June 6, 1955, Ser. No. 513,319

Claims. (Cl. 244-81) It is common in propeller-driven aircraft to provide mechanism which will bar the reversal of the pitch-of the propellers until-the aircraft is ground-borne. In Jetpowered aircraft, reversal of thrust is commonly accomplished by jet-thrust-reversing devices which on touching `down may be moved into operative relationship to the jet issuing from the engines tailpipe, and which at other times may be maintained in a nonoperative position. Incrder to effect reversal of the thrust to the maximum extent possible, the engine must be runV up to maximum thrust just as it would'to develop maximum forward thrust, but this maximum thrust in conjunction with the thrust-reverser effects reversal of the thrust and 'slows' down the forward progress of the aircraft. l

In a reciprocating engine minimum fuel feed, attained by manipulation of the throttle lever, produces idling of lthe engine, 'but not stoppage thereof. Stoppag'e is-accomplished *byv manipulation of a second control, the ignition'switch, to break'the ignition circuit. A:Deceleration of the forward run ,of the aircraft, aftertouching down, is accomplished by manipulation of'still further controls. Because each function is controlledby a ydifferent control device, accidental operation of the wrong control is unlikely. In jet-powered aircraft, on the conf trary, minimum fuel feed produces llame-out or stoppage, yetthe lever` that controls forward thrust should also control rearward thrust, but should be prevented from cutting the fuel supply at any time below a safe idling level. Some other control should be used to accomplish stoppage of the engine when required, so that such occurs only when intended, andnot accidentally. Since both, such controls affect the engines throttle control mechanism, they must be so coordinated with the latter and with each other to insure against unintended or irnproper-operation, under conditions unsuited for any given operation, yet to enable correct operation under proper conditions.

'Y According to the present invention, there is provided a power control mechanism whereby operation of two levers in proper coordination is required to control the engine under all possible conditions, one of these being apower lever by which the thrust developed by the engine may be varied from idling either to full forward, if rotated in one sense, or to full reverse, if rotated in the opposite sense, but operationof the second lever, a start lever,l is required to condition the engine, and' the first lever, for normal operation either forward or reverse as explained above, or for cutting off the operation of the jet engine' by reducing the fuel supply-below the idling level. T he two levers are so coordinated with each other, and with a throttle-control mechanism, as to achieve the abovefresults automatically. In addition, controls are incorporated in the system as a whole to prevent movement of parts into the reversing position except when the aircraft is'ground-borne, and also to prevent movement Yof the thrust-reversing device into reversing position untily the aircraft is ground-borne, but then 'to accomplish its movement into operative position as a result ice sition, and as a prelude to developing full reverse thrust.

Furthermore, as a safety device, there is an interconnection between the two levers, distinct from their operative interconnection, by means or which movement of the'start lever from operating to cut-olf position is prevented except during the time that the power lever is in its idle position.

By such provisions the control of thrust from the jet engine, whetherin flight or on the ground, and for reversing, and the operation of the reversing device, Vis 'made as nearly as possible proof against inadvertent and undesirable movements of the controls, under existing conditions.` p

The general operational plan of the invention having been indicated above, it is believed that the invention will be best understood by describing a representative form as illustrated inthe accompanying drawings, and 'as detailedin this Aspecification hereinafter, and the principles 'of-the invention which lare believed to be new will befdene'd in thecIaimS.

" It should be made'clear that the illustrations are diagrammatic and that the individual elements shown represent only one of variousV possible ways in which various operations and functions can be performed, and in which the several functions may be coordinated and controlled. `The drawings, therefore, are to be looked on in the broad sense asv illustrative and representative, rather than as restrictive.

'Figure l isa diagrammatic illustration of the complete system, .showing parts in the full r 'verse position and with the aircraft ground-borne.

Figure 2 is a similar diagramtof a partof the mec-h4 anism, showing4 parts in the full'forward position. f

Figure 3 is 'a diagrammatic view similar to Figure 2, but showing parts now in l'the cut-'olf position. ff l, l

' Such an aircraft, as the invention is designed tobe installed upon, would'include on or more jet engines 9 supported from thev aircraft structure (not shown) by ineans such as the depending strut 90 beneath awing. To the rear of the engines tailpipe a jet-thrust-reversing device 8 of suitableI form might be associated with, or built intothe' engine, but is herein shown as. separate from the engine, pivotally mounted within the strut 90 at Si), so that it may bev-actuated by an Velectrically controlledY jack or the like at 81 to swing downwardly into A the full-line operative position of Figure 1, where the contacting elements, such as the landing leg 7 mounting the wheel 70, and usually pivotally mounted at Il upon the aircraft structure for retraction and extension. The landing leg, as usual, would incorporate two relatively telescoping elements in association with the usual Vshock absorber, and the relative telescoping' movement of these elements would be depended uponto actuateA or close a squat switch 72 or the like, as is known in the' art, when the aircraft is ground-borne. l' i Throttle-control `mechanism for the engine 9 is diagram; matically illustrated at 98. The precise nature of the same is immaterial so far as the` present invention is con cerned. However, it is assumed to be of atype that may be moved to increase or to decrease the fuel supply to the engine between zero and a maximum limiti-by means` o f a throttle-control device including a rotativey element 3, shown herein as a pulley wheel. Between the element 3 and the throttle control is an operative connection in. dicated by the cables 30. 'f f Mounted upon the aircraft structure convenintly to the pilot or the flight engineer is `a` power'level-"1,A

of the lever in order to. pass the stepl inthe reverse. sense.

Such provisions are common in 'such control levers. yIn addition, the powerlever is provided with. a concentric cam which swings with the'power lever. A start lever 2 distinct from the power lever, is. pivotallylmounted at to swing with relation to a quadrant 24' between an operating position 21 and ay cut-off positionv 22.

These two levers, 1 and 2, are Yoperatively interconnected' with each other and with the rotative element 3 of the throttle-control device by a suitable arrangement, typiiied by the linkage arrangement shown. The link- 16 may be termed, for convenience of reference, the rst link, the link 36 `a second link,` and a link 26 a third link. The link 16 is connected at one end to the power lever 1, or toy the cam extension 15 of vthe. latter; the link-'36, is'conneeted at one end to the rotative elementof theY throttlecontrol device; and the link 26 is connected at one endto the start lever 2, or to the extension 23,. thereof.v The three links 16, 26 and 36 are connected together at a 'common pivot point, indicated at 33,

Again, it is to be emphasized that the mechanism thus described in, 'detail is, merely representative ofv various i meohanisms'thatmght be employed to the end in view, and, that the invention consists primarily in the interconnection and intercontrol between the several mecha.-

nisms, and the particularform of themechanism. illus'- rrated is only a secondary feature of this invention.

To complete the description ofthe mechanism dia',- grammatically shown, the stop 4 will be so positioned in ight as to block swinging of the power lever 1 from its idle position toward its full reverse position, this being in additionto the blockage atforded by the step at 13, This stop 4 isjautomatically controlled,` as by a solenoid 40 incircuit with the squatV switch 72, so that thestop 4 may not be withdrawn from the path of the power lever 1 until the aircraft is fully ground-borne.. When the aircraft is ground-borne,4 however, andthe squat switch V72 is closed, the withdrawal of the.r stop 4 is automatic, either as a result of closure` of the squat switch alone or as, a result of' closure also of the switch 82, described below.A

4 the motor toward or to full thrust. However, since. this thrustV now reacts from the jet-thrust-reversing device 8, the forward progress of the aircraft is slowed to the extent desired. In accomplishingV this end, it is clear that the link 16 is moved from the dot-dash position of Figure l, wherein the link 16 is in line .with the pivots 10 and 33, into the full-line position of Figure l, but since the outer end lof thcjlink 26 is held stationary, link 26 functions only to retain the. iirst'andvse'cond links 16 and 36 in relative dog-leg disposition, and the rocking of the power lever 1 causes rotation of the throttle-control elementl 3 from the idle position to the full power position, which represents fully power. either forward or reverse.` It is equally clear that so long as the third link 26 has its outer end xed,itfis impossible Vforvthe throttle-control element 3 to be rotated from the idle position clockwise toward the cut-off position. Y Figure 2 will showv that rotation of the power lever from the idle positiontothe'full forward position will, in exactly the same manner and to the same. extent, rotate the throttle control element 3 in thesame sense as it was rotated in Figure l to elect full reverse. In Figure 2, however,y thev stop 4 remains in the path of the power lever 1 and the latter canA not be rotated in the sense towardY its' reverse position 12, Vnor can the switch 82 be closed to eiect movementV of the jet-thrust-reversing deviceI 8 to its operative. from its nonoperative position. since they squat switch`72 remains open, the; aircraftbeing air-borne. A

The start lever during all operation. remains inthe operating position,v but when operation is ended, it is its, movement to cut-oil. positionihat closes down. the engine. This must occur onlyjwhen the'engine is, idling, There is, as has been. stated above, an interconnection between the power lever 1 andthe start lever 2 thatbars movement of the startA lever to cut-off position except when the. power-.lever has moved to and4 is. in its idle position. ATo'this end a link 5 isfpivoted at its one end The switch 82 has an actuating element positioned to l be engaged by the cam 15 of theV power lever 1 when the latter moves, from its idle position towards its full reverseV position. The switch 82 will usually be so located that it vcan not be closed until the stop4 has been withdrawn, and movement of the power lever from'its idle toward its full reverse position has been initiated. It might be so located, however, as to be closed by the initial move-y ment of the lever 1 towards its reverse position. When the switch 82 is closed, it being in circuit withthe squat switch 72 and the solenoid 40,A a circuitcis closed by way of 83 to the electric control 84 for the actuator 81., and,

in conjunction with initiation of movement of thepower lever 1 toward its full reverse position4 (which because of blockage by the stop 4 can occur only after the aircraft is fully ground-home), the jet-thrust-reversing device 8 ismoved into operative relationship to the tlpip Qfihe. engine 9. Conversely, its return to nonoperatiye (dashline) Vposition is automatically accomplishedgby return off the powerv lever 1 to its idle positionLwhereinr switch 82; isreopened.

If itbe assumed that the power lever. 1 has been, in its idle position 13, and that-the aircraft has become groundborne, butis rolling forwardly at relatively high, speed, movement off the power lever 1 to the right or toward full reverse position 12. not only moves the. j etgthrustreversing device.. 8. into. operative position.. but runs un,

to the power lever 1 to. move with theplatter, and the link 5 is. suitably guidedV so that its opposite end moves, in conjunction with the power lever 1, inthe vicinity. of the start lever 2. This latter end of the link Sis provided with means, such, for instance, as the aperture 50, and the start lever 2 isv providedwith cooperating means, such .as the, horn 25, which will pass through theI aperture. 5.0, butonly when the aperturer is ina position corresponding tothe idle position of the power lever 1. At all other times the link 5 bars swinging of the -start lever 2, from its operating position. .The position of. parts for cut-oli isV shown in Figure 3,. Here the power lever .1 is in.A its idle position, the horn 25. is in registry with and has enteredthe aperture 50 ofthe link 5, and the start lever 2has been rotated to the right, or clockwise, from the operating position 21 to the cut-off position 22. By thus requiring the use of a separate lever from that used for normal control of the throttle, to eect cutfott-v of the engine, and by making that movement possible, only when the engines normal throttle controlis in idle,v it isv assured that the engine willA only becut'off whenl that isiintended.. and whenl the operationv of the engine is proper for cut'- off.

To eeet. cut-oir, it` is clear that. the outer. end. of; the.V rst lever 16 is held stationary by the xation. of, the power lever 1 in its idle position. at 13 and consequently rotation of the start lever 2 to the right reacts through. the third. link 26 and the second link36, which, lagainare held normally n doggleg, disposition, to eiect rota-v tion of. thethrottle-control, element 3 fromv its. idleffposi.- tion inthe sense oppostely toits movement toward. full powerposition, or intocut-oi'position.

The operative .connection between, the two levers; might vary from that shown, and it is clear that if the power lever 1 were the sole connection to the thlottlereontrl.. element 3, the startv lever- 2 might still be;` connected to, the cables. sain awa-r thatswinginaot thestartlevee S toward cut-olf position would vary the relativeposition of the two runs of the cable, and so effect rotation at'the throttle control 90 .in the proper sense to effect cut-off.

I claim as my invention:

1. Power control mechanism for a jet engine for propulsion of an aircraft, such as includes jet-thrust-reversing means, said power control mechanism including athrottle control device for operative connection to the engine and shiftable in one sense from an idle position to a full power position, and in the other sense from such idle position to a cut-off position; a first pilots control element shiftable in one sense between an idle position and a full forward position, and in the other sense between that idle position anda full reverse position; a second pilots control element shiftable between an operating position and enses a cut-off position; means interconnecting each control element with the throttle control device, and cooperating to shift the latter according to the relative positions of the two pilots control elements, said first element and its interconnecting means being arranged to withhold the throttle control device from movement beyond its idle position towards its cut-olf position so long as the second element and its interconnecting means are in their operating position; and the second element and its interconnecting means being arranged to effect movement of the throttle control device from its idle position to its cutol position while the first element and its interconnecting means are in their idle position.

2. Power control mechanism as in claim l, including auxiliary means interconnecting the two pilots control elements, and shiftable with the rst thereof, arranged to bar movement of the second thereof from its operating position except as the first thereof is in its idle position.

3. Power control mechanism for a jet engine for propulsion of an aircraft, such as includes jet-thrust-reversing means, said mechanism including a throttle control device for operative connection to the engine and shiftable between a full power position through an idle position to a cut-olf position; a first pilots control element shiftable from an idle position in either of two senses to full forward and full reverse power positions, respectively; a second pilots control element shiftable between an operating position and a cut-off position; an operating connection from each of said pilots control elements to said throttle control device, whereby each such element controls the movement of the other; the operating connection from the rst pilots control element including an articulated linkage mechanism which passes through an in-line position, so long as the second pilots control element is in operating position, as that rst element moves in either sense through its idle position; and the operating connection from the second pilots control element including means to shift such articulated linkage mechanism from its in-line position, corresponding to idle of the first element, towards cut-off position, by movement of the second element from its operating to its cut-oli position, and thereby to shift the throttle control device to its cut-oi position, so long as the rst pilots control element is in its idle position.

4. Power control mechanism as set forth in claim 3, including an interconnection between the rst and the second pilots control elements, shiftable with the rst thereof, and positioned relative to the second thereof to block shifting of the latter from its operative position except as the rst element is in its idle position.

5. Power control mechanism as set forth in claim 3, for an aircraft having resilient landing gear, said power control mechanism including means for operative connection to the jet-thrust-reversing means to move the latter into its reversing position, said means being positioned for actuation by shifting of the first pilots control element from its idle position towards its reverse position, means barring such movement of said tirst element, and means for operative connection to the landing gear, operatively connected to said barring means to disable s, the latter and so to enable shifting ofthe first element towards reverse position, upon compression ofthe landing gear by ground engagement thereof. f

l 6. Power control mechanism for a jet engine for propulsion of an aircraft, said power control mechanism includ- Ving a throttle control device for operative connection to the engine and shiftable between a full power position through an idle position to a cut-off position, and the second lever shiftable between an operating position and a cut-off position; an operating connection between said second lever and said throttle control device to shift the latter between 4its idle position and its cut-off position by corresponding movement of the second lever; and means interengageable between the first and second levers to bar movement of the second lever from its operating position towards its cut-off position until the first lever is in its idle position.

7. Power control mechanism for installation in an aircraft powered by a jet engine and provided with jet-thrust reversing means movable into and from reversing position, said power control mechanism comprising a power lever pivotally movable to either side of an idle position into full forward and full reverse positions, respectively, means for operatively connecting said power lever to the thrust-reversing means to move the latter into reversing position upon movement of the power lever towards its reverse position, and vice versa, a start lever pivotally movable between an operating and a cut-oli position, an oscillatable throttle control element having means for operative connection to the engines throttle, and oscillatable from an idle position in one sense to a full power position, and in the opposite sense to a cut-off position, a rst link connected to said power lever and a second link connected to the throttle control element, and pivotally connected to the rst link to maintain the latter in relative dog-leg disposition, whereby to maintain said first link in radial alignment with the power lever so long as the throttle control element remains in its idle position,

- and a Athird link connected to swing with the start lever,

and to the common pivot of the two previously-mentioned links, to etfect movement of the second link and the throttle control element from idle towards cut-off position by corresponding movement of the start-lever, so long as the power lever remains in its idle position.

8. Power control mechanism as in claim 7, including a cam swingable with the power lever, an actuator for operative connection to the thrust-reversing means, located for engagement by said cam, to be shifted and retained in energized position, upon movement of the power lever beyond its idle position towards its reverse position, means located to bar such movement of the power lever, and means operable only while the aircraft is ground-borne to disable said barring means.

9. Power control mechanism as in claim 7, including a link connected to move with the power lever and extending between the latter and the start lever, said link and the start lever having means interengageable to bar movement of the start lever from its operating position towards its cut-off position except while the power lever is in its idle position.

10. Power control mechanism for installation in an aircraft powered by a jet engine and provided with jet-thrust reversing means movable into and from reversing position, said power control mechanism comprising a power lever shiftable to either side of an idle position to full forward and full reverse positions, respectively, an operative connection extending from said power lever to the thrust-reversing means, for connection to the latter, and arranged when so connected to move the latter into reversing position upon movement of the power lever from it'sidie, position towards its reverse position, and vice iversa, `a start lever shiftable between operating and cutoff positions, a throttle controldevice including an osciltlefsaid oscillatable element being` shiftable from an idle position in one sense toY a full power position, and in theop'posite'sense to a cut-off position, a rst link connected at, one end to the powerl'ever, a second link con- 'nected to the oscillatable element of lthe throttlecontrol device, :find a third link, connected at one end to thestart lever, the Irst and third links being pivotallyrc'onnected 4l'fitlzfle element for operative connection to engines throtl :third links, vthe loseill'tlle eleinent of the throttle control device being located, relativeto the irstl and third links, that the second link suhstantially` bisectsl'the angle between the rst yand third links, and'is'moyed thereby 4to. shift said oscillatable elernent between its lll throttle position and'litsfidle position so long asthe first and third Vlinks remainf'in their obtuse-angled relationship, and to shift said oscillatable element from its idle position towards its cut-olf position upon'movement ofthe 'rst and :third levers towards their acute-angled relationship.

ReferencesCited inthe le of this patent Y f VUNITED STATES PATENTS y.Jenkins Dec. 4, 1928 2,331,108l De Ganahl Oct'. y5, Y1943 2,696,079 "Kappus Dec. 7,'19'54 

